A proper warm-up prior to a heavy squat workout allows athletes to handle heavier weight during training sets and train at a higher intensity. Over the long run, being able to train at higher intensities will lead to greater increases in performance, for example, a heavy squat workout increases strength. Often, athletes rush through or skip warm-up sets in an effort to proceed to the higher intensity training sets. When this occurs, athletes usually find that the first set is incredibly difficult while the second set is actually easy. A proper warm-up prepares athletes’ bodies for higher intensity work to come.

Physiological Benefits
There are numerous physiological mechanisms involved in the process of warm-up which are believed to enhance physical performance.
The mechanical efficiency of contracting muscles improves with an increase in muscle temperature; muscle contractions are also more rapid and forceful when the muscle temperature is slightly elevated above normal body temperature.

The warm-up is believed to be especially helpful for athletes in sports or activities which demand complex movements and control of intricate movements occurring in fractions of a second. The concept or phenomenon of “Treppe” occurs when a muscle contracts more forcefully after it has contracted a few times than when it first contracts. This is due to the fact that active muscles require decreasing degrees of succeeding stimuli to elicit maximal contractions. Returning to our example of the second set of squats feeling easier than the first, during the first set there was insufficient warm-up, and the second set felt easier because the first set actually served as a warm-up.

Research evidence concludes that warm-up exercises conducted before an athletic event will prepare the athlete physiologically for better performance due to:
· Increased rate and strength of muscular contraction.
· Increased coordination through activities related to the upcoming training or competition session.
· Injury prevention.
· Endurance warm up brings “second wind” more readily.


Psychological Benefits
A study of athletes that underwent warm-up and were subsequently hypnotized to forget that they warmed up, displayed no measurable improvement in physical performance. Conversely, athletes who imagined a warm-up had enhanced exercise capabilities. The study concluded that athletes who warm up before physical activity tend to be more mentally prepared for practice or competition. One researcher observed that athletes engaged in a warm-up session not only achieved better physical performances but also benefited because they were able to use this time to concentrate on or to visualize their performance.

Based on this information, the warm-up should be specific, using exercises involving movements similar to the actual athletic event or training session but at a reduced level of intensity. This type of warm-up is known as a dynamic warm-up or dynamic flexibility. A majority of strength and conditioning professionals prefer this method of warm-up.


Figure 1

An example of a dynamic warm-up for an athlete performing a weight training session may involve squatting and/or bench-pressing, and he/she may perform squat presses (see figure 1) with a light weight. This exercise is selected for two reasons:

1) it is a total body movement creating a warm-up effect, and
2) it is specific to the exercises that the athlete is going to perform in the actual training session, but during warm-up it is performed at a much lower intensity.

A dynamic warm-up is more applicable to athletic performance than static stretching because it closely duplicates the movement requirements of training or competition. Static stretches, on the other hand, may only improve flexibility and do very little physiologically to warm the athlete for competition or practice.

Static stretching before practice or competition may even have adverse effects, such as calming the athlete, decreasing blood flow and reducing overall strength output. A study tested athletes’ strength production during a leg curl following static or dynamic stretching to discover if significant differences occurred in strength output. Results showed that static stretching compared to dynamic stretching produced a significant reduction in hamstring strength for a time period lasting up to one hour post-stretching. Significantly higher muscle temperature resulted in a more effective static stretch for increasing flexibility. This study supports the use of dynamic flexibility prior to a competition or training session and suggests that static stretching should be used as a post-workout cool down.

Dynamic flexibility training also may be used to teach or emphasize sport-specific movements needed during practice or competition. For example, during the dynamic flexibility warm-up, athletes can practice running mechanics/techniques at a much slower pace than normally taught during a full speed practice.

Conclusion
The design of a warm-up should always be specific to the training session in which athletes are to participate. Dynamic movements are the preferred method of warm-up versus static flexibility, with static flexibility used at the end of the training session.

Design guidelines for warm-up sessions:

• Warm-up should be intense enough to increase body temperature and cause mild perspiration. The session should not fatigue athletes.
• Dynamic movements should dominate the warm-up session.
• Warm-up should include movements common to performance. Maximum effort should be avoided.
• Warm-up for competition should taper off 10 to 15 minutes prior to performance. End the warm-up five minutes before the start of the event.